class MyQueue {
    Deque<Integer> deque = new LinkedList<>();

    void poll(int val) {
        if (!deque.isEmpty() && val == deque.peek()) {
            deque.poll();
        }
    }

    void add(int val) {
        while (!deque.isEmpty() && val > deque.getLast()){
            deque.removeLast();
        }
        deque.add(val);
    }

    int peek() {
        return deque.peek();
    }
}

class Solution {
    public int[] maxSlidingWindow(int[] nums, int k) {
        if (nums.length == 1){
            return nums;
        }
        int len = nums.length - k + 1;
        int[] res = new int[len];
        int num = 0;
        MyQueue myQueue = new MyQueue();
        for (int i = 0; i < k; i++){
            myQueue.add(nums[i]);
        }
        res[num++] = myQueue.peek();
        for (int i = k; i < nums.length; i++){
            myQueue.poll(nums[i-k]);
            myQueue.add(nums[i]);
            res[num++] = myQueue.peek();
        }
        return res;
    }
}

class Solution {
    public int[] topKFrequent(int[] nums, int k) {
        Map<Integer, Integer> map = new HashMap<>();
        for (int num:nums) {
            map.put(num,map.getOrDefault(num,0)+1);
        }
        PriorityQueue<int[]> pq = new PriorityQueue<>((pair1, pair2)->pair2[1]-pair1[1]);
        for (Map.Entry<Integer, Integer> entry : map.entrySet()){
            pq.add(new int[]{
                entry.getKey(),entry.getValue()
            });
        }
        int[] ans = new int[k];
        for (int i =0; i<k;i++) {
            ans[i] = pq.poll()[0];
    }
    return ans;
    }
}